Hermetically sealed rigid or semi-rigid containers, such as trays with a flexible lid sealed around their edges, are widely used in the packaging of food products. This type of packaging offers several advantages: the rigidity of the container provides protection to the contents of the package during transportation, storage and handling, and the hermeticity of the seals contributes to the increase in the shelf-life of the product. In many cases the packaged product is not immediately consumed after opening of the package, forcing the consumer to time-consuming repackaging operations. A reclosable package would therefore be very convenient.
Several attempts have been made in the past to provide reclosable rigid or semi-rigid packages. By way of example, EP-A-1,127,809 describes a food package comprising a container and a cover, said cover being formed by a peripheral clamping element and a lid sealed onto the peripheral clamping element. The lid and the peripheral clamping element are firstly joined together, for instance by injection moulding the peripheral clamping element around the lid, and then joined to the container by sealing the lid to the flange of the container. Alternatively the peripheral clamping element is firstly sealed, welded or glued onto the flange of the container and then the lid is sealed onto the peripheral clamping element. In both cases two separate sealing steps, with two separate sealing tools, are required to hermetically seal the container.
As another example, FR 2,827,841 proposes the use of a composite cover for the closure of a packaging container comprising a peripheral frame whose central opening is closed with a film, whereby an easy-to-open seal is formed between the film and the rim of the packaging container. The packages described in the previous documents are easy to open and can be tightly reclosed due to the cooperation between the peripheral element and the rim of the container but share the disadvantage of requiring separate steps for their assembly, such as the separate assembly of the peripheral element and the film or the need for separate sealing operations, making the whole process cumbersome and costly.
On the other hand FR 2,618,411 describes a package composed of a rigid single-piece container having a ring moulded around its flange and a film sealed onto both the ring and the flange of the container. To open the package the ring is broken away from the flange of the container and the film peeled away from the flange. However, once reclosed, the package of this invention does not offer the required degree of reliability as there is no engagement between the frame and the flange of the container.
Therefore the need still exists for a rigid or semi-rigid container assembly and a package made therewith which can be produced in a limited number of steps, which can be hermetically sealed and which can be tightly and reliably reclosed after opening.
A first objective of the present invention is therefore to provide a rigid or semi-rigid container assembly for the packaging of food products which is reclosable and easy to use. Another objective is to provide a method of packaging a food product by means of the rigid or semi-rigid container assembly and a thermoplastic film sealed onto it to obtain a reclosable package. A further objective of the present invention is to provide a reclosable package comprising the rigid or semi-rigid container assembly, a product placed therein and a hermetically sealed lid in contact with the product.